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Curve Creation on Mac?

Curve Creation on Mac?

2014-11-10 by climballday@...

Forgive me if this is a stupid question, but for the life of me, I cannot figure it out. How do you create custom curves, or look at existing curves in Quadtone Rip on a Mac? I keep seeing references to (Tools>Options>Calibration Mode), but I'm pretty sure that's a windows reference.

I'm still having solarization problems that I was asking about earlier in the summer, and for the life of me, I cannot figure out why (I got incredibly frustrated and gave up on it for a while, then was busy with other things). The head alignment and nozzle checks are excellent, the ink pattern page that prints now is for all intents and purposes absolutely identical to one printed when I wasn't having the problem, and the only thing I can think of is to take a look at the custom curves and look for some kind of issue there, but I cannot figure out how to open it, since I don't see any kind of app in the QTR install folder, and I do all my printing from Photoshop.

For the record:
iMac with Photoshop CS6
OS 10.8.5 Mountain Lion
Epson Artisan 1430 with the Eboni6 inkset. (I have purged and refilled all ink cartridges to be sure, but as I said, the ink pattern page looks exactly as it should).
I haven't dealt with custom curves yet, as I use primarily Epson Hot Press Natural and Moab Entrada Rag Natural, for which good curves exist that I was extremely happy with, previous to all the solarization problems.

The solarization always happens in the same approximate tones (dark grays, but not blacks - so often shadows on faces), so it definitely reads as a curve/ink mixing problem.


Re: Curve Creation on Mac?

2014-11-10 by richard@...

Most often these solarization problems come from mismatching inks or refilling in the wrong order. If you have spare carts, it might be worthwhile refilling from the original bottles and seeing if that alone solves the problem. A couple of the inkjetmall Easy Fill carts for the 1430 are a good to have on hand for tracking down these kinds of problems.

The Calibration mode on the mac is for printing the ink separation files that come with the QTR download. It is a special print mode that fires each channel separately. You use this for setting and measuring the ink limits when creating custom profiles. You can print the ink separation-6 file in calibration mode with QTR print tool or the free adobe color printer utility to bypass color management on the mac. If you have a spectrophotometer you can measure the patches to see which order they are loaded and see if you did mix them up or load them in the wrong order. it is an easy fix with the .qdif (.txt) file, but a little more involved when editing the .quad file.

I just got a 1430 and the EB-6 up and running earlier this week for smaller home use (using larger format printers and Cone inks at the studio). My first tests with the supplied profiles show banding and posterization when printing very smooth gradients. I should be able to post my results with good scans of actual prints later in the week.

Making a 6-ink profile is not exactly hard, but it is an exacting process. The ink channels ramp up pretty fast and they overlap with the other inks more times than the k3 profiles (obviously) so they need to be finely controlled or the errors and defects will be plainly evident in smooth areas.

I used to be pretty relaxed about making K3 profiles, but what I have learned in creating a good number of profiles for 4-6 dilution ink sets over the last year (with QTR) is that the cross-over points need to be very precise and have more overlap (but not too much) to avoid those kinds of problems. Additionally, the test charts and ink separation charts need to be dried for at least 12 hours to stabilize and get an accurate reading—I haven't tested how many minutes/hours under a hair dryer or space heater it takes, but matte black can go from a density of 1.6 to 1.64 over the course of 12 hours (depending on the paper). It might not seem like much of a big deal, but different shades dry down to different percentages which can throw off your overlap calculations if you measure them prematurely. Linearization is also best done with the 21x4 random test chart to account for any variances in the measurement data.

This might have been a little too involved for your question, but I hope it helps.

Richard Boutwell


Re: Curve Creation on Mac?

2014-11-10 by richard@...

There are two ways to look at the QTR "curves" or profiles. If you try to open the .quad file it will open in curve view, which is just the shape of the ink ramp for each channel. If you try to open them in a text editor you will see each channel and then numbers on each of 256 different lines. Those numbers signify the amount of ink at each point along the 256 luminance scale (from 0-100% ink limit, represented as an unsigned 16-bit integer—0 to 65,536). You don't really want to mess with these files or change these numbers around at all since they are created by behind the scenes functions based on the input valued in the .txt/.qdif files. See my post about this here: Quad Tone Rip .quad Files
Quad Tone Rip .quad Files
And how to edit them without setting the house on fire. For those using Quad Tone Rip, you know that you need to first create an ink descriptor file, and install it...
View on www.bwmastery.com
Preview by Yahoo


You can view the .qdif or .txt files that are included with QTR or that people post online. You just need to open them with text edit, and you will be able to see the ink limits for each channel, the gray_val overlap/cross-over points, and linearization, along with toning options when using color inks. There are some other options in there too for refining and tweaking the way the .quad file is created.

I mentioned this in other places, but I started writing a new user guide that goes into more detail about the .txt ink descriptor file and how to get the most out of your profiles without too much unnecessary grief, minimize some of the confusion, and cut down on linearization errors. The more I get into it the more there seems to be, and this is turning into a full on book—along with Excel templates, customized and updated test charts and reference files that allow some automation of some of the curve creation process. I will post more as it develops, but my intention is to make it possible to get professional rip level greyscale printing from qtr and affordable tools.

Richard Boutwell


Re: [Digital BW] Curve Creation on Mac?

2014-11-10 by Paul Roark


Forgive me for not noticing this thread earlier. When I see "Mac" issues, I tend to stop because I9;m Windows. However, when I see Eboni-6 I usually do try to see what is going on, and I didn't see that before I stopped reading.

> ... I'm still having solarization problems ...

>The head alignment and nozzle checks are excellent, the ink pattern page that prints now is for all intents and purposes absolutely identical to one printed when I wasn't having the problem, ...

> Epson Artisan 1430 with the Eboni6 inkset.

There is a possibility that the printer is bad.

Try printing with the Epson driver set to Color Controls, gamma 2.2. That driver is very tolerant of minor ink mixing errors and would cut out QTR and profiles as variables.

Paul
www.PaulRoark.com

Re: Curve Creation on Mac?

2014-11-10 by climballday@...

Okay, let me be more clear.

I know what the calibration mode is, and as noted, I can print a six channel calibration that looks exactly like the one I printed earlier in the year, before I was having the solarization problems. I can also print the 100 step and the 21 step test strip (not in calibration mode, obviously) and they look absolutely perfect. Those things would seem to indicate that all my inks are in the correct order and refilled properly, but just in case, I went back and tried replacing them. I didn't get any different results. All of that was done before I posted this thread.

So I am left with the question, why can I print all the various step tests and calibration tests and have things look perfect, but when I print real prints, I get hard lines in my shadows, instead of smooth gradients?

Re: Curve Creation on Mac?

2014-11-10 by richard@...

I am sorry, i misread the "ink pattern" as the nozzle check pattern. Can you post/link to a picture of the problem you are having.

If the ink separation page prints fine then it indicates the problem is with the profile, although without measuring the ink separation image before and after having the problem you can't really be sure.

Do the lines in the shadows run parallel to the direction the print head travels? If you create a smooth gradient from 50%K-100%K at a diagonal across the page does the solarization show up there too? You could even use the QTR bulls eye targets to see if you get hard jumps with one profile or another.

I created two 1/2"x4" opposing smooth gray ramps/gradients from 0-100 with the gradient tool in photoshop and include it with any new profile—either ones that are supplied or custom ones i create. It will make any problems in the profile with the overlaps and linearization painfully obvious.



Re: Curve Creation on Mac?

2014-11-10 by climballday@...

I've uploaded two samples to flickr, one is the original image being printed, the other is a scan of the printed version. I haven't tried printing a gradient on a diagonal but as I said, the 21 step and 100 step both look good. Maybe next step is printing the diagonal or a curve.

Eboni Carbon Printing Diagnosis
Eboni Carbon Printing Diagnosis
Seamonkey78704's Eboni Carbon Printing Diagnosis set
View on www.flickr.com
Preview by Yahoo

When this first happened, I noticed it after an evening of printing when we were walking around on the wood floors in the studio and my first thought, since it came out of nowhere, was that the bounce from us moving around had somehow messed up the print heads. I spent days doing realignment of the heads and messing with it, to no avail. Later, I did find that I had switched inks in a couple of cartridges, and my yellow cartridge was far out of whack (discovered by printing the ink pattern page). I was absolutely confident that was the problem, so it was a major, major frustration to find that even after going back and purging all the cartridges, triple checking that the correct inks are in them, and getting good ink patterns that look just like my original set up, I'm still having the problem.

Last night I tried completely deleting QTR and all profiles and photoshop preferences from the computer and starting over, with a fresh install, thinking that perhaps I'd inadvertently altered the Moab Entrada profile which I'm using to test everything, but that didn't change it at all either. I really am back to wondering if the printer somehow got messed up, but as I've noted, the nozzle checks, print head alignment and every other test I can run on it all appear normal. I'm frankly at a loss.

Re: [Digital BW] Re: Curve Creation on Mac?

2014-11-11 by Paul Roark

Unless your scanner is way off, that image was not printed with Eboni ink.

Paul
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On Mon, Nov 10, 2014 at 12:46 PM, climballday@... [DigitalBlackandWhiteThePrint] <DigitalBlackandWhiteThePrint@yahoogroups.com> wrote:

I've uploaded two samples to flickr, one is the original image being printed, the other is a scan of the printed version. I haven't tried printing a gradient on a diagonal but as I said, the 21 step and 100 step both look good. Maybe next step is printing the diagonal or a curve.

Eboni Carbon Printing Diagnosis

Eboni Carbon Printing Diagnosis
Seamonkey78704's Eboni Carbon Printing Diagnosis set
Preview by Yahoo

When this first happened, I noticed it after an evening of printing when we were walking around on the wood floors in the studio and my first thought, since it came out of nowhere, was that the bounce from us moving around had somehow messed up the print heads. I spent days doing realignment of the heads and messing with it, to no avail. Later, I did find that I had switched inks in a couple of cartridges, and my yellow cartridge was far out of whack (discovered by printing the ink pattern page). I was absolutely confident that was the problem, so it was a major, major frustration to find that even after going back and purging all the cartridges, triple checking that the correct inks are in them, and getting good ink patterns that look just like my original set up, I'm still having the problem.

Last night I tried completely deleting QTR and all profiles and photoshop preferences from the computer and starting over, with a fresh install, thinking that perhaps I'd inadvertently altered the Moab Entrada profile which I'm using to test everything, but that didn't change it at all either. I really am back to wondering if the printer somehow got messed up, but as I've noted, the nozzle checks, print head alignment and every other test I can run on it all appear normal. I'm frankly at a loss.


Re: Curve Creation on Mac?

2014-11-11 by climballday@...

It's a generic office scanner - not a good photographic one, and I wasn't going for color authenticity, just a quick image to show what effect I'm dealing with. If you want to see the bottles and cartridges, I'm happy to take a photo and show you, but I didn't really feel like I should have to prove that kind of thing.

Re: [Digital BW] Re: Curve Creation on Mac?

2014-11-11 by Paul Roark

Ignoring the color of the print, it looks like the profile, paper and ink are not well matched.

Did you try the Epson driver? It's more tolerant of variations. The Color Controls with gamma 2.2 will be a bit too light, but it should not show shot the flat spots you seem to be getting. See page 6 of http://www.paulroark.com/BW-Info/Eboni-6.pdf for a graph that shows the output compared to the standard gray gamma 2.2.

Paul
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On Mon, Nov 10, 2014 at 7:28 PM, climballday@... [DigitalBlackandWhiteThePrint] <DigitalBlackandWhiteThePrint@yahoogroups.com> wrote:

It9;s a generic office scanner - not a good photographic one, and I wasn't going for color authenticity, just a quick image to show what effect I9;m dealing with. If you want to see the bottles and cartridges, I'm happy to take a photo and show you, but I didn't really feel like I should have to prove that kind of thing.


Re: Curve Creation on Mac?

2014-11-11 by richard@...

I am not sure how the Epson driver will help if it is expecting to spit out color inks that are not loaded. I am not sure how it will show problems with the overlaps and linearization if it doesn't know to fire specific channels for different parts of the gray scale. wouldn't it just be like printing with a black only profile.

I know how hard it can be trying to track down these kinds of problems, especially when there are so many moving variables, so bear with me while i annoy you with more questions... How old are the inks and did you give the bottles a good shake before installing them? Or, are the some of the inks newer/older mix? Is this a new supply of paper? usually these things might not matter as much (aside from pigment settling in the bottle, but all your test charts look good so I am leaning more toward a problem with the profile)

Do you have any Hahnemuhle photo rag or Canson Edition Etching on hand? I have profiles for those papers that don't exhibit the same kind of banding that are evident in the supplied MIS-EB6 profiles. I can send you one to install and see if it is the paper/profile or issue with the printer.

Before we get there though, I have a few other thoughts. can you go to your QTR profiles folder (it should be application>QuadToneRip>Profiles>1430-MIS). Then open the .qdif or .txt file that is giving you problems (in text edit) and then copy and paste all of the text into your response... it should look like this:

PRINTER=Quad1400-MIS
CURVE_NAME=RB-Eb6-HnPhRg
GRAPH_CURVE=YES
N_OF_INKS=6
DEFAULT_INK_LIMIT=0
LIMIT_K=32
LIMIT_C=45
LIMIT_M=45
.
.
.


Then, you navigate to the following folders where the actual profiles that the printer uses: "yourHD">Library>Printers>QTR>quadtone>Quad1400-MIS (or Quad1430-MIS)

Open the profile that is giving you this problem. It should have exactly the same name with a .quad extension instead of .qdif/.txt (this will open in QTR CurveView and show a graph of your ink curves) and then make a screen shot of it to post to the flikr page (cmd+shift+4 will give you the crosshairs for defining the screen capture area).

From your scan, it looks really grainy, and not at all like it was printed from a 6 dilution ink set (i know that is what is loaded, and what is being printed with the calibration page, but if the profile isn't calling for those other inks then they wont fire)

Please post the exact file name of the profile you are using as well.

This should allow us to see if there is something obviously wrong with the profile before moving on the next step (like going Office Space on the damn thing)

Richard Boutwell







Re: [Digital BW] Re: Curve Creation on Mac?

2014-11-11 by Paul Roark

Richard,

The Epson driver (or any driver) doesn't "know" anything. It was written with assumptions about ink densities. Inkset design can incorporate these assumptions and open use to a wider audience. The Eboni-6 design is Epson driver compatible.

In fact, the Epson cross-overs are very flexible and well designed. I have had them work well with cross-overs that range from a dilution ratios of 50% to 20%. That is a huge range that might be able to absorb whatever is going on with the inks (that might well include upstream issues that are no longer worth pursuing).

While you and I may love to play with profiling of third party inksets, most photographers do not. Even if they eventually get down the profiling learning curves, what people need, in my view, is positive feedback -- a good looking print. These issues can be very frustrating, and the Epson driver just might be a way to cut through it all.

Don't get me wrong, I use QTR for all of my B&W printing, but I also think the Epson driver compatibility is an important attribute of an inkset that is aimed at more than techies.

FWIW

Paul

Re: [Digital BW] Re: Curve Creation on Mac?

2014-11-11 by David Kachel

The Eboni-6 design is Epson driver compatible.

Paul,

I must admit this baffles me completely. My take on this is that the Epson driver is only going to use a gray ink in the Yellow slot if it thinks a part of the image needs to be yellow, etc. To me, this means that various gray tones are going to be laid down in areas that make no sense at all.

Please elaborate for those of us who are IQ challenged.

;-)

David Kachel

___________________

Artist-Photographer
Fine B&W Photographs

WEBSITE: www.davidkachel.com
BLOG: thetransparentphotographer.com
EMAIL: david@...

PO Box 93
Fort Davis, TX 79734
(432) 386-5787


Re: [Digital BW] Re: Curve Creation on Mac?

2014-11-11 by Paul Roark

David,

Drivers don't "think." The program just tells the printer to spit out inks according to the assumptions the programmers had about relative ink densities, with allocations among the color channels that were made to balance the assumed color inks.

So, the M-LM and C-LC Epson ink dilution ratio is approximately 30% dense ink to 70% clear base. Eboni-6 uses the same ratios for these same ink positions.

The drive assumes a dense black ink is in the K position, as it is in virtually all B&W inksets also.

The yellow color ink is very light in terms of density. So is Eb6-Y.

The fact that the Eb6 inks are shades of gray is irrelevant to what the driver does. The driver is clueless. If a grayscale file is the input, it's converted to CLcMLMYK according to how much of each of the OEM inks would be needed to make a neutral looking print. The fact that OEM inks are not in the carts is not a variable in the program (combination of computer software and printer firmware).

What is amazing about the Epson driver is that it can handle the huge variances in grayscale relative densities that I noted before. The main question I had with the beta Carbon Variable Tone inkset is whether the driver could handle a second K in the Y position. Amazingly, it did. Although, as I've noted in the PDF, the cross-over issues at the black end are tricky; I recommend people just copy the ends of the PS curves I've published. I had to use 1% step wedges to get the response curves smooth there.

Hope this helps ...

Paul

Again, I use QTR, not the Epson driver for my B&W printing. All of us on this forum are here for a reason. But, at one point Bob Zeiss disclosed to me that the MIS customer base was about 30,000 people. While I suspect that is now ancient history, I have not idea. The point is that this forum is not composed of average users. I work with high end fine art photographers/printers who use the Epson driver for Eboni-6. Profiling a rip is beyond what most people want to deal with.

Paul
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On Tue, Nov 11, 2014 at 8:02 AM, David Kachel david@... [DigitalBlackandWhiteThePrint] <DigitalBlackandWhiteThePrint@yahoogroups.com> wrote:

The Eboni-6 design is Epson driver compatible.

Paul,

I must admit this baffles me completely. My take on this is that the Epson driver is only going to use a gray ink in the Yellow slot if it thinks a part of the image needs to be yellow, etc. To me, this means that various gray tones are going to be laid down in areas that make no sense at all.

Please elaborate for those of us who are IQ challenged.

;-)

David Kachel

___________________

Artist-Photographer
Fine B&W Photographs


PO Box 93
Fort Davis, TX 79734



Re: [Digital BW] Re: Curve Creation on Mac?

2014-11-11 by cameronrneilson@...

Hello fellow BW Fine Art printers,

I have to chime in and say that Paul has done an outstanding job of outlining and dissecting the black and white Carbon printing process. I poured over the papers and, though confusing at first read, I eventually fulfilled the learning curve through some tinkering and now feel invincible in my printing.

I recently had my fine art portfolio prints reviewed in New York where two of the reviewers said that the b/w prints I showed were the most beautiful, detailed, and intricate prints they had EVER seen--these are veterans in the industry too. This assures my opinion that I've successfully surpassed my darkroom prints.

In regards to Epson versus QTR drivers, I admit I'm actually a bit more pleased with the Epson. This could be a result of my hardware (r1800 with Eboni 6 printed on Epson Hot Press Bright). QTR works very well too, I just prefer the Epson at this point. This may very well change when I change to a larger printer.

Paul, keep up the great research and thanks for all of your insight.

Thanks
Cameron

Re: [Digital BW] Re: Curve Creation on Mac?

2014-11-11 by David Kachel

Paul,

So, the M-LM and C-LC Epson ink dilution ratio is approximately 30% dense ink to 70% clear base. Eboni-6 uses the same ratios for these same ink positions.

Damn, and me out of Bourbon!

I still don\u2019t get it. And it seems (above) that you are saying that four ink positions (M, LM, C and LC) in the Eboni-6 set all have the exact same dilution gray ink in them?
I don\u2019t follow. OEM M, LM, C and LC can\u2019t be all the same dilutions, can they?

Maybe it would help to know the dilutions of all the Eboni-6 inks and those of the OEM inks. Can you tell us what they are?

You also seem to be saying that when a grayscale image is sent to an Epson driver in a printer with OEM inks in it, that all inks are used equally in order to get a grayscale image?
That might explain my observation the other day when my gray OEM inks failed, that there was a lot of Cyan ink underneath very dark areas of a monochrome (brown) print.

But then, I look at this sentence:

The main question I had with the beta Carbon Variable Tone inkset is whether the driver could handle a second K in the Y position.

… And I am right off the rails again. Isn\u2019t the OEM driver laying down a very low density ink here? Then I would think the heavy black would throw everything off?!



David Kachel

___________________

Artist-Photographer
Fine B&W Photographs

WEBSITE: www.davidkachel.com
BLOG: thetransparentphotographer.com
EMAIL: david@davidkachel.com

PO Box 93
Fort Davis, TX 79734
(432) 386-5787


Re: Curve Creation on Mac?

2014-11-11 by climballday@...

Hi Richard and Paul,

To answer your questions above:

The problem happened rather suddenly, within one evening of printing (in late July), showed up in extremely mild ways in a few prints (<5) and then got bad enough to notice, at which time, going backwards, I realized that it hadn't started all at once. The inks I am using now are all from the same bottles that produced some extremely nice prints before hand, were all purchased at the same time, around one year ago. It is part of my procedure to shake the bottles before filling the syringes, and extra care was taken to do that when I went through and purged and refilled all of the cartridges, after the problem happened.

Paul, speaking to your question, the print you're seeing was printed on Moab Entrada Natural paper, using the following settings:

Color Handing: Photoshop manages color
Printer Profile: QTR_RGB_Matte_Paper
Rendering Intent: Perceptual
with black point compensation checked.

Under the Quadtone Rip Preferences, I have chosen Eb6-Moab-Entrada-Natural-12-2011 under Curve 1, with all settings at 100% and no other curves chosen.

(( Interestingly Richard, when I go into the QTR applications folder, and look in the 1400-1430-MIS folder, the eb6 profiles aren't there... just MK and PK profiles. I vaguely recollect having to install profiles in a different way last year, when I set things up initially. Looking in the Library didn't lead me to them... I'll have to look further. ))

Resolution is set at 2880dpi unidirectional, and all other selections at 0 or default.

The effect happens at both 8-bit and 16-bit settings.

I want to specify again, I was getting really gorgeous prints with the entire setup until I wasn't. I'm uploading a couple examples of the stuff I printed before the problem, including another portrait from before, and printed now, with the same settings as before exhibiting the issue. Here's the link again:

Eboni Carbon Printing Diagnosis
Eboni Carbon Printing Diagnosis
Seamonkey78704's Eboni Carbon Printing Diagnosis set
View on www.flickr.com
Preview by Yahoo

Also, Paul, I have tried looking for a way to print straight from the Epson driver, as per the basic overview that comes with QTR, but I can't seem to find a way to do that on the Mac. I have tried printing straight from Preview, and while it was a crappy print, it did not exhibit the behavior, which makes me think it is a QTR issue.

I deeply appreciate the help trying to sort this problem out. As I said, I was quite happy with the prints I was getting before, which makes the bad ones all the more frustrating.

Stephen

Re: [Digital BW] Re: Curve Creation on Mac?

2014-11-11 by Paul Roark

David,

It's the ratio of the darker to lighter inks in a cross-over that matter, not the absolute values.

Yes, the Y=K setup is a bit off the rails, but it was worth a try, and, amazingly, it worked. I'm not sure yet what future it might have.

(The rest is background FWIW. Then I'm out of here for a while.)

Stepping back to the problems that may have started this thread, consistence of the materials is a real problem. I've had talks with Epson employees who acknowledge that even Epson faces differences from one batch of ink to another. If they have problems, you can imagine what MIS and Jon Cone face.

What lit a fire under me and got my ink experimenting going this time was that I ran out of Eboni and bought a new batch. It crashed my system. It took me a fair amount of work to know what was going on because the paper batch was also new. However, I keep samples of old paper and ink, and a few draw-downs of the inks and prints on old paper nailed the problem; it was the ink.

So, I went to the wholesale source and got a sample of the current batch. It's a bit different, but good enough that I have to move forward, since I have printing that needs to be done. So, I've ordered a liter of the MK and new empty carts for the 7800. All the old ink is going to be trashed, and I'll re-profile for the new batch and use it to mix my own ink as long as it lasts.

Right now, MIS's concerns are, among other things, whether the new owner of IS can deliver consistent product. It's not a trivial issue. Even the wholesaler really only does part of the processing and is dependent on upstream suppliers.

So, what is a consumer to do? Knowing how to make and re-linearize profiles really helps. Mixing my own inks also helps.

For most users, this level of control is not realistic. So, making profiles that are relatively tolerant of variables is part of what I am now trying to do. If you look at Jon's curves, you'll note that he uses long trailing edges on the curves with lots of overlap. This helps. What I've recommended in the past also is to take some of the gray inks in the Eb6 set and make them a "toner" channel so that there are more overlaps. The beta "carbon variable tone" even in the Epson driver is going to run a single MK the full length of the scale. This sets up a "backbone" that will be totally unaffected by variables. Some of my profiles do other rather unorthodox things that might help with these issues.

Then again for my best prints, I use the standard, what I call "serial" partitioning of QTR and push the dmax up to the limit. But while a fine-tuned racing engine may be great on the track, it may not be what you want on the street. So, Epson pulls the ink limit down and makes cross-overs that are tolerant of variables.

Some of what I'm doing with the QTR profiles is and will be aimed at dealing with the real world problems of variability that is inevitable and can be very frustrating, discouraging the use of approaches that really ought to be more widespread.

Paul
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On Tue, Nov 11, 2014 at 10:36 AM, David Kachel david@... [DigitalBlackandWhiteThePrint] <DigitalBlackandWhiteThePrint@yahoogroups.com> wrote:

Paul,

So, the M-LM and C-LC Epson ink dilution ratio is approximately 30% dense ink to 70% clear base. Eboni-6 uses the same ratios for these same ink positions.

Damn, and me out of Bourbon!

I still don’t get it. And it seems (above) that you are saying that four ink positions (M, LM, C and LC) in the Eboni-6 set all have the exact same dilution gray ink in them?
I don’t follow. OEM M, LM, C and LC can’t be all the same dilutions, can they?

Maybe it would help to know the dilutions of all the Eboni-6 inks and those of the OEM inks. Can you tell us what they are?

You also seem to be saying that when a grayscale image is sent to an Epson driver in a printer with OEM inks in it, that all inks are used equally in order to get a grayscale image?
That might explain my observation the other day when my gray OEM inks failed, that there was a lot of Cyan ink underneath very dark areas of a monochrome (brown) print.

But then, I look at this sentence:

The main question I had with the beta Carbon Variable Tone inkset is whether the driver could handle a second K in the Y position.

… And I am right off the rails again. Isn’t the OEM driver laying down a very low density ink here? Then I would think the heavy black would throw everything off?!



David Kachel

___________________

Artist-Photographer
Fine B&W Photographs


PO Box 93
Fort Davis, TX 79734


Re: [Digital BW] Re: Curve Creation on Mac?

2014-11-11 by David Kachel

Paul,

Is there a paper anywhere on this? Just not getting it.


David Kachel

___________________

Artist-Photographer
Fine B&W Photographs

WEBSITE: www.davidkachel.com
BLOG: thetransparentphotographer.com
EMAIL: david@...

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Re: [Digital BW] Re: Curve Creation on Mac?

2014-11-12 by Dr. Elliot Puritz

If YOU are worried about MIS inks then surely we must consider alternative sources as necessary.  It would be too time consuming to profile every batch of new ink . 

When will the new inks be available?  Will the new manufacturer be testing each "run"? Should we be buying up the current inks? Questions after questions with few concrete answers.

Elliot

Sent from my iPhone
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> On Nov 11, 2014, at 2:19 PM, "Paul Roark roark.paul@... [DigitalBlackandWhiteThePrint]" <DigitalBlackandWhiteThePrint@yahoogroups.com> wrote:
> 
> David,
> 
> It's the ratio of the darker to lighter inks in a cross-over that matter, not the absolute values.
> 
> Yes, the Y=K setup is a bit off the rails, but it was worth a try, and, amazingly, it worked.  I'm not sure yet what future it might have.
> 
> (The rest is background FWIW.  Then I'm out of here for a while.)
> 
> Stepping back to the problems that may have started this thread, consistence of the materials is a real problem.  I've had talks with Epson employees who acknowledge that even Epson faces differences from one batch of ink to another.  If they have problems, you can imagine what MIS and Jon Cone face.
> 
> What lit a fire under me and got my ink experimenting going this time was that I ran out of Eboni and bought a new batch.  It crashed my system.  It took me a fair amount of work to know what was going on because the paper batch was also new.  However, I keep samples of old paper and ink, and a few draw-downs of the inks and prints on old paper nailed the problem; it was the ink.
> 
> So, I went to the wholesale source and got a sample of the current batch.  It's a bit different, but good enough that I have to move forward, since I have printing that needs to be done.  So, I've ordered a liter of the MK and new empty carts for the 7800.  All the old ink is going to be trashed, and I'll re-profile for the new batch and use it to mix my own ink as long as it lasts.
> 
> Right now, MIS's concerns are, among other things, whether the new owner of IS can deliver consistent product.  It's not a trivial issue.  Even the wholesaler really only does part of the processing and is dependent on upstream suppliers.
> 
> So, what is a consumer to do?  Knowing how to make and re-linearize profiles really helps.  Mixing my own inks also helps.  
> 
> For most users, this level of control is not realistic.  So, making profiles that are relatively tolerant of variables is part of what I am now trying to do.  If you look at Jon's curves, you'll note that he uses long trailing edges on the curves with lots of overlap.  This helps.  What I've recommended in the past also is to take some of the gray inks in the Eb6 set and make them a "toner" channel so that there are more overlaps.  The beta "carbon variable tone" even in the Epson driver is going to run a single MK the full length of the scale.  This sets up a "backbone" that will be totally unaffected by variables.  Some of my profiles do other rather unorthodox things that might help with these issues.
> 
> Then again for my best prints, I use the standard, what I call "serial" partitioning of QTR and push the dmax up to the limit.  But while a fine-tuned racing engine may be great on the track, it may not be what you want on the street.  So, Epson pulls the ink limit down and makes cross-overs that are tolerant of variables.  
> 
> Some of what I'm doing with the QTR profiles is and will be aimed at dealing with the real world problems of variability that is inevitable and can be very frustrating, discouraging the use of approaches that really ought to be more widespread.
> 
> Paul
> www.PaulRoark.com 
> 
>> On Tue, Nov 11, 2014 at 10:36 AM, David Kachel david@... [DigitalBlackandWhiteThePrint] <DigitalBlackandWhiteThePrint@yahoogroups.com> wrote:
>> Â 
>> Paul,
>> 
>> So, the M-LM and C-LC Epson ink dilution ratio is approximately 30% dense ink to 70% clear base.  Eboni-6 uses the same ratios for these same ink positions.  
>> 
>> Damn, and me out of Bourbon!
>> 
>> I still don’t get it. And it seems (above) that you are saying that four ink positions (M, LM, C and LC) in the Eboni-6 set all have the exact same dilution gray ink in them?
>> I don’t follow. OEM M, LM, C and LC can’t be all the same dilutions, can they?
>> 
>> Maybe it would help to know the dilutions of all the Eboni-6 inks and those of the OEM inks. Can you tell us what they are?
>> 
>> You also seem to be saying that when a grayscale image is sent to an Epson driver in a printer with OEM inks in it, that all inks are used equally in order to get a grayscale image?
>> That might explain my observation the other day when my gray OEM inks failed, that there was a lot of Cyan ink underneath very dark areas of a monochrome (brown) print.
>> 
>> But then, I look at this sentence:
>> 
>> The main question I had with the beta Carbon Variable Tone inkset is whether the driver could handle a second K in the Y position.
>> 
>> … And I am right off the rails again. Isn’t the OEM driver laying down a very low density ink here? Then I would think the heavy black would throw everything off?!
>> 
>> 
>> 
>> David Kachel
>> 
>> ___________________
>> 
>> Artist-Photographer
>> Fine B&W Photographs
>> 
>> WEBSITE: www.davidkachel.com
>> BLOG: thetransparentphotographer.com
>> EMAIL: david@...
>> 
>> PO Box  93
>> Fort Davis, TX 79734
>> (432) 386-5787
> 
>

Re: [Digital BW] Re: Curve Creation on Mac?

2014-11-12 by Dr. Elliot Puritz

Congratulations on the photos!  Do you have a link?

Elliot

Sent from my iPhone
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> On Nov 11, 2014, at 10:04 AM, "cameronrneilson@... [DigitalBlackandWhiteThePrint]" <DigitalBlackandWhiteThePrint@yahoogroups.com> wrote:
> 
> Hello fellow BW Fine Art printers,
> 
> I have to chime in and say that Paul has done an outstanding job of outlining and dissecting the black and white Carbon printing process.  I poured over the papers and, though confusing at first read, I eventually fulfilled the learning curve through some tinkering and now feel invincible in my printing. 
> 
> I recently had my fine art portfolio prints reviewed in New York where two of the reviewers said that the b/w prints I showed were the most beautiful, detailed, and intricate prints they had EVER seen--these are veterans in the industry too.  This assures my opinion that I've successfully surpassed my darkroom prints.  
> 
> In regards to Epson versus QTR drivers, I admit I'm actually a bit more pleased with the Epson.  This could be a result of my hardware (r1800 with Eboni 6 printed on Epson Hot Press Bright).  QTR works very well too, I just prefer the Epson at this point.  This may very well change when I change to a larger printer.
> 
> Paul, keep up the great research and thanks for all of your insight.
> 
> Thanks
> Cameron 
> 
>

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